Hydrofining-reforming process

ABSTRACT

Hydrocarbon feedstocks containing organic sulfur are subjected to a two-stage hydrofining treatment. In the first stage a sulfided hydrofining catalyst is utilized to effect hydrodecomposition of the bulk of the sulfur compounds and produce an effluent containing, e.g., about 0.5-10 ppm of residual sulfur. In the second stage, the first stage product is contacted with a molybdenum-Group VIII metal hydrofining catalyst maintained at least partially in a reduced state, so as to effect a substantial and more efficient hydrodecomposition of the remaining sulfur compounds. The two-stage process is particularly useful for the pretreatment of naphtha feedstocks to a subsequent reforming step employing highly sulfur-sensitive catalysts such as the bimetallic platinum-rhenium-alumina composites.

[111 3,884,797 1451 May 20, 1975 HYDROFlNlNG-REFORMING PROCESS [75] Inventors: Starling K. Alley, Jr., Brea; Edward C. Attane, Jr., Orange, both of Calif.

[73] Assignee: Union Oil Company of California,

Los Angeles, Calif.

[22] Filed: Sept. 10, 1973 [21] App]. No.: 395,931

Related US. Application Data [63] Continuation-impart of Ser. No. 183,793, Sept. 27,

1971, abandoned.

[52] US. Cl.. 208/89; 208/210 [51] Int. Cl Cl0g 23/04; ClOg 31/14 [58] Field of Search 208/89, 210

[56] I References Cited UNITED STATES PATENTS F550 A/A PHTf/A Primary ExaminerDelbert E. Gantz Assistant ExaminerJames W. Hellwege Attorney, Agent, or FirmLannas S. Henderson; Richard C. Hartman; Dean Sandford [57] ABSTRACT Hydrocarbon feedstocks containing organic sulfur are subjected to a two-stage hydrofining treatment. In the first stage a sulfided hydrofining catalyst is utilized to effect hydrodecomposition of the bulk of the sulfur compounds and produce an effluent containing, e.g., about 05-10 ppm of residual sulfur. In the second stage, the first stage product is contacted with a molybdenum-Group VIII metal hydrofining catalyst maintained at least partially in a reduced state, so as to effect a substantial and more efficient hydrodecomposition of the remaining sulfur compounds. The twostage process is particularly useful for the pretreatment of naphtha feedstocks to a subsequent reforming step employing highly sulfur-sensitive catalysts such as the bimetallic platinum-rhenium-alumina composites.

12 Claims, 1 Drawing Figure PATENTED MAY 2 0197s 6'1480L/NE 1 HYDROFINING-REFORMING PROCESS RELATED APPLICATIONS This application is a continuation-in-part of Ser. No. 183,793, filed Sept. 27, 1971, and now abandoned.

BACKGROUND AND SUMMARY OF INVENTION Catalytic hydrofining processes as commonly practiced in commercial applications utilize a presulfided catalyst composite of a Group VIB metal and an iron group metal supported on a refractory oxide carrier such as alumina. The presulfided catalyst is regarded as being more active than catalysts which are initially put on-stream in an oxidized or reduced form, later becoming sulfided by contact with feed sulfur. In most hydrofining operations, the objective is to reduce the feed sulfur content to somewhere in the range of about 2-50 ppm. Perhaps the most well known application of hydrofining in this area involves the pre-treatment of naphtha feedstocks to reduce the sulfur content to about 2-10 ppm for subsequent conversion to high octane gasoline in a platinum-alumina reforming zone. As is well known, these platinum-alumina catalysts are poisoned by sulfur compounds, but nevertheless can be most tolerate small amounts of sulfur in the range of about 2-5 ppm. The small poisoning effect of sulfur in this concentration range is more than offset by the savings achieved by operating the hydrofining zone for in complete desulfurization.

It will thus be seen that the choice as to hydrofining severity to be used in pretreating reformer feedstocks involves an economic balance between the benefits to be gained in the reforming zone versus the added expense required in the hydrofining zone (in the form of increased catalyst volume required, or decreased catalyst life resulting from using more severe hydrofining conditions). When using conventional presulfided hydrofining catalysts, and conventional platinum-alumina reforming catalysts, this economic balance has generally dictated controlling the hydrofining operation to produce a reformer feed containing from about 2 -10 ppm of sulfur.

However, with the advent of the newer bimetallic platinum-rhenium-alumina reforming catalysts, this picture has changed somewhat. The bimetallic reforming catalysts offer the advantages over conventional platinum-alumina catalysts of giving higher yields and longer life. But the evidence now appears to indicate that these advantages largely disappear if the feed to the reformer is not almost completely sulfur-free. It has been found for example that there is a very significant difference in catalyst deactivation rates as between the reforming of feedstocks containing 2.0 ppm versus 0.2 ppm of sulfur. There is thus a stronger incentive when using the bimetallic reforming catalysts to seek ways of improving desulfurization efficiency in the hydrofining step.

In hydrofining, the hydrodesulfurization reaction is generally considered to conform to first order kinetics as expressed by the rate constant equation, K=LHSV In SJS where S; represents sulfur in the feed, and S represents sulfur in the product. From this equation, it will be seen that under a given set of hydrofining conditions conforming to a rate constant of, e.g., 8.0, it would require about a 50 percent increase in catalyst volume to reduce the sulfur content of a feed originally containing 1,000 ppm of sulfur to 1 ppm instead of 10 ppm. Thus, it requires only one volume of catalyst to reduce the sulfur content of such a feed from 1,000 to 10 ppm, and 1.5 volumes to reduce the sulfur content from 1,000 to 1 ppm. If the same objective is pursued by raising the hydrofining temperature so as to increase the rate constant while using the same volume of catalyst, the permissible run length is considerably shortened. Hence, it will be seen that either of these alternatives involve significant added expense.

The foregoing however does not completely delineate the added expense involved in desulfurizing to very low sulfur levels, below 5 ppm. The kinetics discussed above are an optimistic oversimplification. The same rate constant obviously cannot apply to all of the very different types of sulfur compounds found in any given feedstock. Some compounds such as mercaptans and sulfides are very easily decomposed, whereas others such as thiophenes are relatively more difficult. In heavy gasolines, it has been found that still more difficultly decomposable sulfur compounds, presumably of the condensed ring thiophene types, also are found. When these compounds are present in the feed, they will comprise most of the sulfur remaining ina feed which has been hydrofined to a sulfur level of, e.g., about 1-20 ppm. When operating under conditions corresponding to a rate constant of 8 as discussed above, the actual rate constant pertaining to these refractory sulfur compounds will be substantially lower, perhaps in the order of 1-2. Hence, in the case illustrated above, it would actually require at least doubling the catalyst volume to obtain a product containing 1 ppm of sulfur instead of 10 ppm.

According to our invention, instead of increasing the severity or size of the primary hydrofining zone,we provide a separate post-treatment zone, termed a hydrosorption zone, which is operatedin'the absence of hydrogen sulfide and with a reduced form of hydrofining catalyst. We have discovered'thatthe residual, refractory sulfur compounds which strongly iresist' hydrofdecomposition in a conventional sulfided catalyst sys} tem, are much more readily"decom'posed by hydrogenation and cracking in contact with a hydrofining catalyst in which the active components are in a reduced form, reduced for example with hydrogen at elevated temperatures.

In the preferred adaptation of the process as a pretreatment for reformer feedstocks, the hydrosorption zone is operated integrally with the reforming zone, i.e., with total effiuent from the hydrosorption zone going to the reformer without intervening condensation, depressuring or purification. It has been found that the reduced hydrofining catalyst is not only more efficient for converting refractory sulfur compounds, but that it acts as an efficient sorbent for the hydrogen sulfide which is generated. Since the washed effiuent from the conventional hydrofiner normally contains only about 1-10 ppm of sulfur, a very large volume of such effluent can be treated in the hydrosorption zone before the catalyst is completely converted to a sulfide form, resulting in breakthrough of H S in the effluent therefrom. Thus, it will be seen that the hydrosorption zone acts both as a hydrorefining zone and as a guard chamber for the reformer. If desired, a pair of swing reactors may be provided, operated alternately on feed contacting and regeneration cycles, whereby one of the hydrosorption reactors may be maintained on stream at all times. Preferably the hydrosorption zone is operated at essentially the same pressure as the reformer whereby both Zones may be incorporated in the same recycle gas loop, with a single compressor serving both zones.

In addition to the foregoing, we have discovered that for the above-discussed hydrosorption purposes, conventional'mixed Group VIB-Group VIII metal hydrofining catalysts are not equivalent in their reduced state for the hydrodecomposition of thiophene-type compounds. Specifically, it has been found that combinations of molybdenum with Group VIII metals are much more active at temperatures above about 575F than. presumably equivalent combinations of tungsten with Group VIII metals. Accordingly, we employ for hydrosorption purposes the molybdenum-Group VIII metal combinations, and utilize temperatures above about 575F. Strangely enough, at temperatures below 575F, the molybdenum-and tungsten-containing catalysts appear to be approximately equivalent in activity. US. Pat. No. 3,714,030 discloses a two-step desulfurization process in which a benzene feedstock is first partially desulfurized over a conventional Group VIB Group VIII catalyst, and then over a metallic nickel catalyst to reduce the sulfur level to below about 1 ppm. We have found however that the combination of nickel with molybdenum is much more effective than nickel alone, while the tungsten-nickel combination appears to be approximately equivalent to nickel alone.

DETAILED DESCRIPTION Hydrofining Conditions Broad Range Preferred Range Temperature, F S 850 650 825 Pressure, psig 300 3000 800 2000 LHSV 0.4 l0 1 5 H /Oil Ratio, MSCF/B 0.5 l 10 These conditions are suitably adjusted and correlated so as to reduce the feed sulfur content to between about 0.2 and 20, preferably 0.5 and 10, ppm.

Effluent from hydrofiner 6 is withdrawn via line 10, cooled to, e.g., about l00200F in heat exchanger 12, mixed with wash water injected via line 14, and transferred into high pressure separator 16, from which recycle gas is withdrawn via line 4. The aqueous phase in separator 16, containing substantially all of the ammonia generated in hydrofiner 6, and a substantial proportion of the hydrogen sulfide, is withdrawn for disposal via line 18. High-pressure condensate in separator 16 is then flashed via line 20 into low-pressure separator 22, from which light hydrocarbon flash gases are exhausted via line 24. The low-pressure condensate in separator 22 is then transferred via line 26 to stripping column 28 into which fresh makeup hydrogen is injected at the bottom thereof via line 30 to strip out remaining traces of H 8 from the liquid condensate. Hydrogen-rich stripping gases containing some H 8 are taken overhead from stripper 28 via line 32 and blended with the recycle hydrogen in line 4.

Stripped condensate from stripper 28 is withdrawn via line 34, blended with hydrogen-rich recycle gas from reformer 36 via lines 38 and 40, and then passed via preheater 42 into one of the swing hydrosorbers 44 and 46, the flow being suitably controlled by means of valves 48, 50, 52 and 54. Hydrosorbers 44 and 46 are filled with a suitable hydrofining catalyst initially in a reduced or oxidized form. In either case it is believed that the operative form of the catalyst is a reduced form, inasmuch as the oxide forms are rapidly reduced by the feed-hydrogen mixture. The on-stream hydrosorber is slowly, over a period of many days or several months, converted to a sulfide form, as detected by the presence of H S in the off-gases therefrom. When this occurs the illustrated valving arrangement is manipulated to shift the flow of feed to the other by drosorber while the off-stream unit is being regenerated.

Suitable operating conditions to be maintained in the onstream hydrosorber are as follows:

Hydrosorption Conditions Broad Range Preferred Range Temperature, "F 575 800 600 750 Pressure, psig I00 800 300 600 LHSV 5 30 I0 25 H /Oil Ratio, MSCF/B 0.2 15 0.5 5

It will be understood that the foregoing conditions are suitably adjusted and correlated so as to maintain the desired minimum value of sulfur in the effluent therefrom. Normally, when using a bimetallic catalyst in reformer 36, it is desirable to maintain sulfur values below 2 ppm, and preferably below 1 ppm.

Regeneration of the exhausted catalyst beds in hydrosorbers 44 and 46 is carried out by conventional procedures, involving first the stripping out of adsorbed hydrocarbons, followed by oxidation with oxygencontaining gases at temperatures between about 700 and l200F. Regeneration is complete when the offgases are substantially free of S0 Following oxidation, the catalyst may be again placed on-stream as such, but preferably it is first reduced in a stream of hydrogen at temperatures of about 700-l200F, until the off-gases are substantially free of water.

Desulfurized effluent from hydrosorber 44 or 46 is passed directly via line 56 and preheater 58 into reformer 36. If desired a portion of the recycle gas in line 38 may be diverted via line 60 to blend with the hydrosorber effluent in line 56. In reformer 36, which is filled with a suitable reforming catalyst described hereinafter, reforming takes place under the following general conditions:

Reforming Conditions Broad Range Preferred Range Temperature, F 750 1050 850 1000 Pressure, psig I00 800 300 600 LHSV 0.4 8 l 5 Il /Oil Ratio, MSCF/B 0.5-- 15 l 10 Those skilled in the art will readily und'erstand that the foregoing, conditions are suitably adjusted and correlated so as to achieve the desired yield-octane values.

Effluent from reformer 36 is withdrawn via line 62 and passed via condenser-heat exchanger 64. into high- B. Catalysts Operative catalysts for use in hydrofiner 6 comprise essentially ane one or more of the Group VIB metals in combination with any one or more of the Group VIII metals, in sulfided form. Specifically, any of the sulfides of molybdenum, tungsten or chromium may be used in combination with any of the sulfides of ,iron, cobalt, nickel, palladium or platinum, either alone or supported on a suitable refractory oxide carrier such as alumina, silica, zirconia, titania, clays, etc. Preferably the carrier should have a relatively low cracking activity, corresponding to a Cat-A cracking activity index below about 25. Preferred combinations comprise a sulfide of molybdenum and/or tungsten combined with a sulfide of nickel and/or cobalt. Specifically preferred composites consist of about 1-8 weight-percent of nickel as NiO and about 5-30 weight-percent of molybdenum as M00 supported on an activated alumina carrier. These catalysts are well known in the art and hence need not be described in detail, except to observe they are ordinarily employed in the form of pellets or extrudates ranging in size from about l/32-inch to A-inch in diameter.

Sulfiding procedures are also well known in the art and hence need not be described in detail. Normally, following impregnation with the active metals, the catalyst is first calcined in air to form an oxide-form, and then the sulfided form is produced by passing a stream of gas containing hydrogen sulfide through the catalyst bed at temperatures ranging between about 200 and 1200F.

Operative catalysts for use in hydrosorbers 44 and 46 are of the molybdenum-Group VIII metal type described above for use in hydrofiner 6, except that they.

are initially placed on stream in anoxidized or reduced state. Preferably the calcined catalyst is subjected to a prereduction treatment with hydrogen at temperatures between about 500 and l200 F until the effluent gas becomes substantially free of water vapor. By this treatment, the reducible metal oxides on the catalysts are converted either to free metals or to lower valent oxides. In this form they combine readily with the hydrogen sulfide generated in the hydrosorbers, forming metal sulfides. It is preferred to employ catalysts containin g sufficient molybdenum and Group VIII metal to provide a sor ption capacity for H 8 of =at"least about 3 weight-percent, preferably at least 5 weight-percent, expressed as elemental sulfur. Preferred metal contents range between about 4 and 10 weight-percent NiO and- /or CoO, combined with about 15-35 weight-percent ofMoO V Suitable catalysts for use in reformer 36 may comprise any one or more of the Group VIII noble metals supported on a porous refractory metal oxide carrier such as alumina. The preferred catalysts comprise about 0.2-2 weight-percent of platinum and about 0.2-2 weight-percent of 'rhenium supported on an activated alumina carrier. Optionally, the catalyst may also contain a combined halogen, preferably chlorine; in amounts ranging between about 0.2 and 3 weightpercent. Suitable such catalysts are disclosed for example in U.S. Pat. No.' 3,415,737.

C. Feedstocks Feedstocks which may be desulfurized by the process of this invention include substantially any sulfurcontaining hydrocarbon fraction boiling in the range of about to l200F. The two-stage desulfurization technique is however of greatest value for treating feedstocks which contain more than about 200 parts per million .of sulfur. Exemplary feedstocks include gasolines and naphthas, kerosene, turbine fuel, petroleum solvents and the like. Naphtha feedstocks for reforming The following examples illustrate the critical aspects of the invention, but are not to be construed as limiting in scope:

EXAMPLE I Two parallel reforming runs were carried out under severe conditions selected to accelerate deactivation rates of the respective catalysts, and thus to demonstrate the sensitivity of platinum-rhenium reforming catalysts to very small amounts of sulfur in the feed. The initial feedstock was a blend of hydrofined gasoline with a boiling range of 212-408F, and containing 0.9 ppm of sulfur. For Run A sufficient thiophene was added to a portion of thisifeed to provide a total sulfur content of 2.0 ppm; for Run B another portion of this feed was further hydrofined to reduce t'he sulfur level to 0.2 ppm. Both runs were carried out at 200 psig, 2.0 LI-ISV with 5,000 SCF of hydrogen per barrel of feed, and with the temperature adjusted to give a product having an average research clear octane number of 100.5.

' while run B required only 955F. This spread in temperature at 180 hours, when translated into terms. of catalyst activity, means that the catalyst in run A was only about 50 percent as active as. the catalyst in run B at 180 hours. In both of these runs, the initial catalyst was a commercial reforming catalyst containing 0.33 weight-percent platinum, 0.34 weight-percent rhenium, and 1.0 weight-percent chloride, supported on a predominantly eta alumina base having a surface area of 4 74'm /g. It is evident from the foregoing data that this catalyst is quite sensitive to very small amounts of sulfur in the feedstock.

EXAMPLE II A hydrosorption catalyst of this invention was prepared by reducing a calcined composite of 3 weightpercent NiO and 18 weight-percent M supported on a 99% Al O SiO base. The reduction was carried out by heating the catalyst in hydrogen to 700F in 2.5 hours, holding 2'hours at 700F, and then reducing the temperature to about 550-600F for feed introduction. The feedstock was a naphtha having the same boiling range as the feed of Example I, and which had been previously hydrofined over a sulfided nickelmolybdenum-alumina catalyst to a residual sulfur content of 1.7 ppm. Four hydrosorption runs were carried out at 400 psig and 20 LI-ISV, using 4,000 SCF of hydrogen per barrel of feed. The results of these runs at various temperatures were as follows:

Example ll (Ni-Mo) Temp, "F

Ill (Ni-W) IV (Ni-W) To achieve these same sulfur levels by adding incremental sulfided catalyst to the initial hydrofining zone in which the sulfur was previously reduced to 1.7 ppm, would require at least about ten times the volume of the reduced catalyst employed in this example.

EXAMPLE Ill Temperature, F. Sulfur in Product, ppm

Another hydrosorption catalyst was prepared containing 5 weight-percent nickel as NiO and 22 weightpercent tungsten as W0 supported on a base consisting of about 3 weight-percent of a rare earth X zeolite dispersed in a predominantly silica gel matrix. This catalyst was prereduced in hydrogen as described in Example II, and then tested for desulfurization activity, employing the same feed and reaction conditions as described in Example II. At various temperature levels the results were as follows:

Temperature, F. Sulfur in Product, ppm

Desulfurization at 400 psig Sin Product, ppm

S in Feed,

Ll-ISV N lo o \l\l\l\l LILILI LILILILI 9. 9 5 aroma who The marked superiority of the Ni-Mo catalyst of Example is readily apparent.

It is not intended that the invention should be limited to exemplary details described herein; the true scope of the invention is intended to be defined by the following claims and their obvious equivalents.

We claim:

1. A process for the hydrodesulfurization of a sulfurcontaining hydrocarbon feedstock, at least a portion of the sulfur in said feedstock appearing in compounds comprising a thiophene ring, which comprises:

1. contacting said feedstock plus added hydrogen with a sulfided Group VIB and Group VIII mixedmetal hydrofining catalyst under hydrofming conditions adjusted to reduce the organic sulfur content of said feedstock to between about 0.2 and 20 2. separating hydrogen sulfide from the resulting intermediate product oil; and

3. contacting said intermediate product oil plus added hydrogen with a hydrogen-reduced, initially substantially sulfur-free molybdenum and Group VIII mixed-metal hydrofining catalyst under hydrofining-sorption conditions adjusted to effect a further substantial reduction in the organic sulfur content thereof and sorption of substantially all of the fining catalysts recited in steps (I) and (3) each comprise nickel and molybdenum supported on activatedalumina.

4. A process as defined in claim 1 wherein the liquid hourly space velocity in step (3) is between about and 25.

5. A process as defined in claim 1 wherein step (3) is continued until break-through of hydrogen sulfide in the effluent therefrom, and the catalyst employed therein is then regenerated to remove sulfur therefrom and then placed back on-stream.

6. A process for the hydrodesulfurization and reforming of a sulfur-containing naphtha feedstock, at least a portion of the sulfur in said feedstock appearing in compounds comprising a thiophene ring, which comprises:

l. contacting said feedstock plus added hydrogen with a sulfided Group VIB and Group VIII mixedmetal hydrofining catalyst under hydrofining conditions adjusted to reduce the organic sulfur content of said feedstock to between about 0.5 and 10 2. separating hydrogen sulfide from the resulting intermediate gasoline product; v

3. contacting said intermediate gasoline product plus added hydrogen with a hydrogen-reduced, initially substantially sulfur-free molybdenum and Group VIII mixed-metal hydrofining catalyst under hydrofining-sorption conditions adjusted to effect a further substantial reduction in the organic sulfur content thereof, to a level below about 2 ppm, and also to sorb substantially all of the hydrogen sulfide thereby generated on said hydrogen-reduced hydrofining catalyst, said hydrofining-sorption conditions including a temperature above about 5 F; and

4. subjecting total effluent from step (3) to catalytic reforming in contact with a sulfur-sensitive Group VIII noble metal reforming catalyst.

7. A process as defined in claim 6 whereins said reforming catalyst recited in step (4) comprises platinum and rhenium.

8. A process as defined in claim 6 wherein steps (3) and (4) are carried out at substantially'the same pressure, and wherein hydrogen-rich recycle gas from step (4) is recycled to step (3). g

9. A process as defined in claim 6 wherein the hydrofining catalysts recited in steps (I) and (3) each comprise nickel and/or cobalt molybdenum supported on a refractory, porous oxide carrier.

10. A process as defined in claim 6 wherein the hydrofining catalysts recited in steps (1) and (3) each comprise nickel and molybdenum supported on activated alumina. 4

11. A process as defined in claim 6 wherein the liquid hourly space velocity in step (3) is between about 10 and 25.

12. A process as defined in claim 6 wherein step (3) is continued until break-through of hydrogen sulfide in the effluent therefrom, and the catalyst employed and then placed back on-stream. 

1. CONTACTING SAID FEEDSTOCK PLUS ADDED HYDROGEN WITH A SULFIDED GROUP VIB AND GROUP VIII MIXED-METAL HYDROFINING CATALYST UNDER HYDROFINING CONDITIONS ADJUSTED TO REDUCE THE ORGANIC SULFUR CONTENT OF SAID FEEDSTOCK TO BETWEEN ABOUT 0.5 AND 10 PPM;
 1. contacting said feedstock plus added hydrogen with a sulfided Group VIB and Group VIII mixed-metal hydrofining catalyst under hydrofining conditions adjusted to reduce the organic sulfur content of said feedstock to between about 0.2 and 20 ppm;
 1. A process for the hydrodesulfurization of a sulfur-containing hydrocarbon feedstock, at least a portion of the sulfur in said feedstock appearing in compounds comprising a thiophene ring, which comprises:
 1. contacting said feedstock plus added hydrogen with a sulfided Group VIB and Group VIII mixed-metal hydrofining catalyst under hydrofining conditions adjusted to reduce the organic sulfur content of said feedstock to between about 0.5 and 10 ppm;
 2. separating hydrogen sulfide from the resulting intermediate gasoline product;
 2. separating hydrogen sulfide from the resulting intermediate product oil; and
 2. A process as defined in claim 1 wherein the hydrofining catalysts recited in steps (1) and (3) each comprise nickel and/or cobalt plus molybdenum supported on a refractory, porous oxide carrier.
 2. SEPARATING HYDROGEN SULFIDE FROM THE RESL ULTING INTERMEDIATE GASOLINE PRODUCT;
 3. A process as defined in claim 1 wherein the hydrofining catalysts recited in steps (1) and (3) each comprise nickel and molybdenum supported on activated alumina.
 3. contacting said intermediate product oil plus added hydrogen with a hydrogen-reduced, initially substantially sulfur-free molybdenum and Group VIII mixed-metal hydrofining catalyst under hydrofining-sorption conditions adjusted to effect a further substantial reduction in the organic sulfur content thereof and sorption of substantially all of the resulting hydrogen sulfide on said hydrogen-reduced hydrofining catalyst, said hydrofining-sorption conditions including a temperature above 575*F.
 3. CONTACTING SAID INTERMEDIATE GASOLINE PRODUCT PLUS ADDED HYDROGEN WITH A HYDROGEN-REDUCED, INITIALLY SUBSTANTIALLY SULFUR-FREE MOLYBDENUM AND GROUP VIII MIXED-METAL HYDROFINING CATALYST UNDER HYDROFINING-SORPTION CONDITIONS ADJUSTED TO EFFECT A FURTHER SUBSTANTIAL REDUCTION IN THE ORGANIC SULFUR CONTENT THEREOF, TO A LEVEL BELOW ABOUT 2 PPM, AND ALSO TO SORB SUBSTANTIALLY ALL OF THE HYDROGEN SULFIDE THEREBY GENERATED ON SAID HYDROGEN-REDUCED HYDROFINING CATALYST, SAID HYDROFINING-SORPTION CONDITIONS INCLUDING A TEMPERATURE ABOVE ABOUT 575*F; AND
 3. contacting said intermediate gasoline product plus added hydrogen with a hydrogen-reduced, initially substantially sulfur-free molybdenum and Group VIII mixed-metal hydrofining catalyst under hydrofining-sorption conditions adjusted to effect a further substantial reduction in the organic sulfur content thereof, to a level below about 2 ppm, and also to sorb substantially all of the hydrogen sulfide thereby generated on said hydrogen-reduced hydrofining catalyst, said hydrofining-sorption conditions including a temperature above about 575*F; and
 4. A process as defined in claim 1 wherein the liquid hourly space velocity in step (3) is between about 10 and
 25. 5. A process as defined in claim 1 wherein step (3) is continued until break-through of hydrogen sulfide in the effluent therefrom, and the catalyst employed therein is then regenerated to remove sulfur therefrom and then placed back on-stream.
 4. subjecting total effluent from step (3) to catalytic reforming in contact with a sulfur-sensitive Group VIII noble metal reforming catalyst.
 4. SUBJECTING TOTAL EFFLUENT FROM STEP (3) TO CATALYTIC REFORMING IN CONTACT WITH A SULFUR-SENSITIVE GROUP VIII NOBLE METAL REFORMING CATALYST.
 6. A PROCESS FOR THE HYDRODESULFURIZATION AND REFORMING OF A SULFUR-CONTAINING NAPHTHA FEEDSTOCK, AT LEAST A PORTION OF THE SULFUR IN SAID FEEDSTOCK APPEARING IN COMPOUNDS COMPRISING A THIOPHENE RING, WHICH COMPRISES:
 7. A process as defined in claim 6 whereins said reforming catalyst recited in step (4) comprises platinum and rhenium.
 8. A process as defined in claim 6 wherein steps (3) and (4) are carried out at substantially the same pressure, and wherein hydrogen-rich recycle gas from step (4) is recycled to step (3).
 9. A process as defined in claim 6 wherein the hydrofining catalysts recited in steps (1) and (3) each comprise nickel and/or cobalt molybdenum supported on a refractory, porous oxide carrier.
 10. A process as defined in claim 6 wherein the hydrofining catalysts recited in steps (1) and (3) each comprise nickel and molybdenum supported on activated alumina.
 11. A process as defined in claim 6 wherein the liquid hourly space velocity in step (3) is between about 10 and
 25. 12. A process as defined in claim 6 wherein step (3) is continued until break-through of hydrogen sulfide in the effluent therefrom, and the catalyst employed therein is then regenerated to remove sulfur therefrom and then placed back on-stream. 